For the mining operation of mines and the like, there is a need for the autonomous travel technology to use unmanned machines to carry out mining work with the aim of improving the safety and reducing the costs. At a mining site, after a work machine such as a hydraulic excavator or the like excavates minerals and/or a topsoil layer, the excavated minerals and/or topsoil layer must be hauled to the outside of the mining site. Such haulage work is carried out by a work machine such as a dump truck and the like, which has a body (vessel) capable of carrying minerals and/or topsoil layer and having a relatively high maximum load capacity.
As one of conventional techniques in the autonomous travel technology using a work machine of this type such as a dump truck, for example, an autonomous travel system is proposed to implement travel control of a vehicle for autonomous traveling without an onboard operator on the basis of own-vehicle position information calculated by a positioning device, such as using GPS (Global Positioning System) or the like, mounted on the work machine.
In the autonomous travel system, the own-vehicle position calculated by the positioning device is transmitted to a control center over wireless communications. The control center generates a transportation course from a loading site at which a work machine such as a hydraulic excavator or the like loads minerals and/or topsoil layer, to a dumping site at which a work machine such as a dump truck or the like dumps the minerals and/or topsoil layer, and generates a target route in a working site such as a loading site, dumping site and/or the like. Then, the control center transmits target route information as data indicating the target route to the work machine such as a dump truck or the like.
For the transportation course, the target route of the work machine is generated based on mine map data generated from trajectory information of the work machine, such as a dump truck or the like, previously obtained by the positioning device. Also, for the working site, a target route is generated, for example, from an entrance to a loading point to the loading point set near the work machine such as a hydraulic excavator or the like.
In contrast, the map data includes boundary information indicating a boundary. The boundary is generated by being extracted from a travel trajectory of the work machine, such as a dump truck or the like, the travel trajectory being included in the own-vehicle position information calculated by the positioning device, and the boundary defines a travelable area capable of being travelled by a work machine and a non-travelable area incapable of being travelled by a work machine. The boundary information is used to prevent interference between a boundary line in map data and a target route when the target route for the transportation course and the working site as described above are generated. Thus, the map data is required to be updated frequently as the work process proceeds.
To address this, the following patent literature 1 is known as one of conventional techniques to update map data. The patent literature 1 discloses “an unmanned-vehicle guidance device that guides an unmanned vehicle to travel along a guide course on the basis of a travel position of the unmanned vehicle measured by travel position measuring means and course data defining the guide course for the unmanned vehicle, the unmanned-vehicle guidance device comprising: means that inputs data on boundary lines of a course area; means that generates course data; means that infers interference between the unmanned vehicle and the boundary lines of the course area when the unmanned vehicle is traveled along the guide course defined by the generated course data; course data changing means that changes the course data if the interference is inferred; recognizing means that recognizes which of all segments of the boundary lines of the course area changes in shape of the boundary line; and course-area boundary-line updating means that updates data on the boundary lines of the course area in respect of only the segment with the changed shape of the boundary line of all the segments of the boundary lines of the course area, in which the recognizing means includes a work machine moving the course area, moving position measuring means that measures a moving position of the work machine, and means that specifies the segment with the changed shape of the boundary lines of all the segments of the boundary lines of the course area on the basis of the moving position of the work machine.”